Hot Water Creeping Back to Water Pump….HELP!

[astgerma]

Good morning folks,

When I am hooked up to city water and my hot water tank is on.

I will get hot water backup to my 12 volt water pump and causes that pump to leak water at the seem.

Please help!!!

[Dr4Film]

Sounds like you have a failed or missing check valve.

Time to trace the water lines to see what you have currently  plus what you will need to deal with to correct this problem 

[Tom Cherry]

36 minutes ago, astgerma said:

Good morning folks,

When I am hooked up to city water and my hot water tank is on.

I will get hot water backup to my 12 volt water pump and causes that pump to leak water at the seem.

Please help!!!

Don’t know what brand of pump you have or how the Monacrch’s are plumbed as we don’t get a lot of questions on them.  Read the above topic.  There is a good explanation.  If your fresh water tank starts to fill up or, probably, in your case, getting hot water back.

FWIW, you CAN put in a check valve.  But you have to totally gut your pump to remove the check valve and some folks that have gone to a stand-alone check valve report a reduction of flow and pressure.  The built in check valves have less restriction.  The household ones are designed higher flow and pressures.  One fix.  Install, if convenient, a shut off valve on the output and isolate the pump so the hot water cannot work its way back.

BTW….hot water WILL migrate….it is called a thermal syphon.  I installed a line on my home hot water heater drain, without a check valve and ran it all the way to my kitchen faucet and put it in on a “T” and the thermal loop keeps the water instantly hot.

[astgerma]

Thanks for your suggestions .  To add a check valve in the line sounds like a good way to go.

That is what I will do first.

Thanks again, Andy

[tmw188]

Curious if this is a new issue or you’ve had it for some time?

[Tom Cherry]

4 hours ago, astgerma said:

Thanks for your suggestions .  To add a check valve in the line sounds like a good way to go.

That is what I will do first.

Thanks again, Andy

It would better to isolate the issue.  If the check valve failed and the pump is OK, then order a new check valve for the pump.  Don't know if you have the Remco RV55 or a Surflo.  BOTH have them inside.  You can get a parts break down.  Instead of breaking lines and putting in a heavy duty commercial or residential valve, which might severely restrict the flow....as many others in many other topics within the past year have done....determine WHY the check valve, that worked for years failed.  It probably just wore out of the rubber seal on it or the spring.  Spending $8 - $10 and having the pump perform like it did before rather than much more on a brass one and also then having very low flow or pressure....that is up to you.

Obviously your MH....but this is the experience of others.

[astgerma]

I will take a look at the pump and see if the check valve has failed.

[Tom Cherry]

19 minutes ago, astgerma said:

I will take a look at the pump and see if the check valve has failed.

I am no expert on the SurFlo but on the Remco (AquaTech) RV55, it is on the outlet end and pops in.  There is picture of it in the topic that I posted.  You can get a parts breakdown of whatever pump you have by googling and then odds are, Amazon or one of the RV online houses has a replacement.  That check and the impeller and the pressure control areas ...and I guess the motor are the common failures.  Sometimes if it is simple like popping in a check valve, you save a lot and don't throw out a really good item just because a known to fail item does.

Good Luck.  Let us know and also the pump name and model and such.  WE all learn that way...

Thanks...

[Garage Monster]

I have an older Monaco but mine has a valve at the city water connection that must be in one position to fill the tank and the other position to use city water.  Perhaps a failure at that point. 

[Tom Cherry]

2 hours ago, Garage Monster said:

I have an older Monaco but mine has a valve at the city water connection that must be in one position to fill the tank and the other position to use city water.  Perhaps a failure at that point. 

A failure, and we have had some there, will allow the fresh tank to overflow.  Usually debris and cycling under pressure is the fix….usually works.  

There is also a separate check valve in most Monaco systems, but it is to keep the system pressurized so the pump works and is a back flow preventer for the CG.  Otherwise you would have to put a cap or plug in the water connection hose inlet.  These will not result in overfilling or hot water migtating.

Some Monaco’s actually had a city fill valve with a check in it….but very few based on the posts here.

The most likely scenario, and it depends on how close the hot water heater is, to the pump….as far as the length of the pipe, is a bad check valve in the outlet side of the pump.  All Monaco pumps, based on what folks post here, came with the built in check valve.

NOW….using your post as a means of getting info out….the topic that I linked was about the REMCO RV55.  ORIGINALLY that pump, used from the mid to late 2000’s, was manufactured by the original company and called AQUATECH.  REMCO later bought the rights or the manufacturing equipment or whatever and they sell it now.

FOR WHATEVER REASON, they stopped including the check valve, although the packaging and such said it had one.  It MUST have one to work.  They nave have changed the packaging now.  We have had many folks install as a replacement for a Surflo or when their pump went bad.  Depending on CG water pressures, some have reported overflowing fresh tanks.  Those that don’t use a regulator and the pressures are high….the most issues.

Thats how we became “more familiar” with the systems 

[astgerma]

21 hours ago, tmw188 said:

Curious if this is a new issue or you’ve had it for some time?

I have had this coach for 15 years and this is the first time that I have had hot water migrating backwards to the 12 volt pump.

[Tom Cherry]

1 hour ago, astgerma said:

I have had this coach for 15 years and this is the first time that I have had hot water migrating backwards to the 12 volt pump.

The suggestions that I made are about as good as I can do, based on what you posted and some knowledge of the plumbing and such.  MY GUESS....if you marked the level of the fresh tank and came back and checked it, you are getting it filled (slowly) and where you Hot water tank is....is close to the pump.  Therefore, if the check valve failed....it would then be logical, knowing the dynamics of thermal syphoning, for the heated water to migrate.

NOW....not knowing your hot water tank or such....as I have an AquaHot, if it had a check valve in it....to prevent this...then it could be the cuprit.

Do some digging....check the pump.  You MAY have difficulties in finding a part for a 15 year old pump....or not.  That's about as much as I can offer....strange things happen.  I would definitely DOWNLOAD or look at the manual for the Hot Water Tank or go there and see the plumbing and check for an external check valve...or call the vendor and ask them.  If they say NO CHECK....then it is logical to fix the pump. 

Just out of curiosity....where is the Hot water heater and approximately how many feet of pipe is there.  If it is close by....as in the next compartment....then logic says the check valve in the pump has failed and you have hot water in the pump....which also means you have extra water in the fresh tank...as that is the way it is (or should have been) plumbed....

[Tom Cherry]

https://liveworkdream.com/2018/08/01/fix-rv-water-heater-check-valve/#:~:text=NOTE%3A The check valve on,plumbing to enter back in.

EDIT and ADDITIONAL INFORMATION.  Did a little research.  I was NOT aware that a RV Hot Water Heater had a Check Valve.  Maybe your's does....and after 15 years...it has failed.  The above article is good. 

I also posted (and cannot TYPE above it) a great video on how it works.  NOW....our MH's already have the City/Fill fitting...but if you look and follow the video, then it makes a little more sense....

SO...focus, I THINK, on the Hot Water Heater.  Google that....

[windsorbill06]

On 4/25/2023 at 7:37 AM, astgerma said:

Good morning folks,

When I am hooked up to city water and my hot water tank is on.

I will get hot water backup to my 12 volt water pump and causes that pump to leak water at the seem.

Please help!!!

Andy, 

You say this is a new issue and the "water pump leaks at the seam" now.  Is there a chance you over pressurized the system from the city water hookup?  Do you have a pressure regulator connected at the source?  I've seen water pressures in excess of 100-110#'s, and that will damage these coaches. (houses too, for that matter)

[astgerma]

Yes I do have a pressure regulator installed. 

It seem like when hot water tank gets hot it creates more pressure and migrates hot water back to the 12 volt pump and causes it to leak at the seam.

[tmw188]

Have you noticed if your water htr pressure relief valve is leaking also?

Edited April 27, 2023 by tmw188

[Tom Cherry]

1 hour ago, astgerma said:

Yes I do have a pressure regulator installed. 

It seem like when hot water tank gets hot it creates more pressure and migrates hot water back to the 12 volt pump and causes it to leak at the seam.

Yes, but odds are it is a bad check valve in the heater.  Read the article in the link.  I’d go there first and not the pump.  This is beginning to make sense now.

Good luck and keep us posted.  When you replace the valve shoot some pictures.  It would be beneficial to also post the WH brand and model and a part number for the check.  We will add it to the parts list.

[astgerma]

After looking at all the recommendations from all that replied to this problem.

I want you to know that it was the check valve on the pump.

I priced the check valve at $51.00 and a new pump at $70.00.  I found the pump on Amazon.

I elected to go for a new pump to eliminate any future problems.

I thank you all for your advice.

Andy

Edited May 2, 2023 by astgerma

[Tom Cherry]

45 minutes ago, astgerma said:

After looking at all the recommendations from all that replied to this problem.

I want you to know that it was the check valve on the pump.

I priced the check valve at $51.00 and a new pump at $70.00.  I found the pump on Amazon.

I elected to go for a new pump to eliminate any future problems.

I thank you all for your advice.

Andy

Andy,

Good deal.  FWIW, from a fluid dynamics point of view, odds are the check valve in the hot water heater has failed.  From a flow stand point, the check valve in the pump kept the hot water from “backing out”.  But the internal check valve, assuming your hot water heater has one like the video and article, had failed earlier.  But the check valve in the pump prevented the heated water from backing out and crawling or migrating along the inlet.

However, the leaky check valve in the pump also prevented water from backing up, under pressure, and then filling up your fresh tank.

Problem solved at the pump, but not at the real source.  

Glad you were able to fix it.  Would you please post the brand and model of the pump and the Amazon replacement.  @Frank McElroy will then add to our parts list.  We don’t have much info on the Monarch, but will include this in the plumbing section.

Thanks for the follow up.

[astgerma]

9 minutes ago, Tom Cherry said:

Andy,

Good deal.  FWIW, from a fluid dynamics point of view, odds are the check valve in the hot water heater has failed.  From a flow stand point, the check valve in the pump kept the hot water from “backing out”.  But the internal check valve, assuming your hot water heater has one like the video and article, had failed earlier.  But the check valve in the pump prevented the heated water from backing out and crawling or migrating along the inlet.

However, the leaky check valve in the pump also prevented water from backing up, under pressure, and then filling up your fresh tank.

Problem solved at the pump, but not at the real source.  

Glad you were able to fix it.  Would you please post the brand and model of the pump and the Amazon replacement.  @Frank McElroy will then add to our parts list.  We don’t have much info on the Monarch, but will include this in the plumbing section.

Thanks for the follow up.

Precitrade Shurflo 2088-554-144 Fresh Water Pump, 12 Volts, 3.5 Gallons Per Minute, 45 Psi  (Can be purchased on Amazon)

[astgerma]

1 hour ago, Tom Cherry said:

Andy,

Good deal.  FWIW, from a fluid dynamics point of view, odds are the check valve in the hot water heater has failed.  From a flow stand point, the check valve in the pump kept the hot water from “backing out”.  But the internal check valve, assuming your hot water heater has one like the video and article, had failed earlier.  But the check valve in the pump prevented the heated water from backing out and crawling or migrating along the inlet.

However, the leaky check valve in the pump also prevented water from backing up, under pressure, and then filling up your fresh tank.

Problem solved at the pump, but not at the real source.  

Glad you were able to fix it.  Would you please post the brand and model of the pump and the Amazon replacement.  @Frank McElroy will then add to our parts list.  We don’t have much info on the Monarch, but will include this in the plumbing section.

Thanks for the follow up.

Where would the check valve in the water heater be???

There is a one way valve at the outlet of the hot water tank

 

[Tom Cherry]

12 hours ago, astgerma said:

Where would the check valve in the water heater be???

There is a one way valve at the outlet of the hot water tank

 

Read the article and look at the video I posted for you.  IF you have checkvalve or oneway valve on the outlet...then the pressure can NOT go back into the tank.  If there is no backflow or pressure....then the hot water will not migrate.  When I say "migrate"....you have some thermal heating of the inlet pipe....but due to the fact that it is not insulated, then it quickly becomes ambient....in simpler terms....you MIGHT feel a smidge difference in the inlet side of the tank....say 12" back that the outlet temperature say 12".  Bottom LINE....an internal check valve or an external one on the outlet will do the same.  SO....

The one funky thing in this....you MAY have actually had two things go wrong....or a failure that allowed another, earlier failure to become an issue....and here is my logic.

If the one way valve (check) failed or is not working....then the pressure on the OUTLET was letting water be pushed back into the tank.  That would have resulted in hot water flowing back to the outlet of the pump.  SO....when the pump check valve failed....you had NO back flow prevention.

Bottom line....the one way valve on the Outlet of the hot water tank sounds like it is not working....but as long as the pump check valve was in place....then that was holding back the water.  I think that I would either replace the check valve or figure out HOW to disconnect the inlet line....and cap or plug it off.  Then pressurize the system.  If water flows OUT of the inlet of the hot water tank....you know the valve has failed.

That's the logic.  You actually have TWO backflow or check valves...and as long as the pump one was working....FINE...but when it failed....BINGO, the pump got hot.  Hope that makes sense...